1. Field
Embodiments of the present invention relate generally to optoelectronic communication devices. More specifically, the present invention relates to an optical transceiver module in which diagnostic data and control functions are externally accessible during transceiver operation.
2. The Relevant Technology
Computing and networking technology have transformed our world. As the amount of information communicated over networks has increased, high-speed transmission has become ever more critical. Many high-speed data transmission networks rely on optical transceivers and similar devices for facilitating transmission and reception of digital data embodied in the form of optical signals over optical fibers. Optical networks are thus found in a wide variety of high-speed applications ranging from as modest as a small Local Area Network (LAN) to as grandiose as the backbone of the Internet.
Typically, data transmission in such networks is implemented by way of an optical transmitter (also referred to as an electro-optic transducer), such as a laser or Light Emitting Diode (LED). The electro-optic transducer emits light when current is passed there through, the intensity of the emitted light being a function of the current magnitude through the transducer. Data reception is generally implemented by way of an optical receiver (also referred to as an optoelectronic transducer), an example of which is a photodiode. The optoelectronic transducer receives light and generates a current, the magnitude of the generated current being a function of the intensity of the received light.
Various other components are also employed by the optical transceiver to aid in the control of the optical transmit and receive components, as well as the processing of various data and other signals. For example, such optical transceivers typically include an electro-optic transducer driver (e.g., referred to as a “laser driver” when used to drive a laser signal) configured to control the operation of the optical transmitter in response to various control inputs. The optical transceiver also generally includes an amplifier (e.g., often referred to as a “post-amplifier”) configured to perform various operations with respect to certain parameters of a data signal received by the optical receiver. A controller circuit (hereinafter referred to the “controller”), which is the focus here, controls the operation of the laser driver and post amplifier.
In addition to controlling the operation of the laser driver and the post amplifier, the controller may collect and manage diagnostic data. Performance characteristics of an optical transmitter and receiver may vary in response to changes in operational conditions like temperature and voltage. For example, the threshold current and slope efficiency of a laser diode vary with temperature. To ensure the quality and integrity of data transmission, various measurement and compensation circuits may be employed by a transceiver to compensate for these changes. The transceiver controller may evaluate operating conditions, such as, but not limited to, temperature, voltage, and low frequency changes (such as receive power) from the post-amplifier and/or from the laser driver, and then adjust component settings to compensate for any changes. The operating condition parameter values, referred to collectively as “diagnostic data”, may also be evaluated by the host computer system which typically has access to the controller via a serial interface.
In addition to, and sometimes in conjunction with managing diagnostic data, a controller may also drive several other transceiver functions, including, but not limited to, the following: (i) setup functions which generally relate to the required adjustments made on a part-to-part basis in the factory to allow for variations in component characteristics such as laser diode threshold current; (ii) identification information identifying the transceiver type, capability, serial number, and compatibility with various standards; (iii) eye safety and general fault detection which are used to identify abnormal and potentially unsafe operating parameters and to report these to the user and/or perform laser shutdown, as appropriate; (iv) temperature compensation functions which compensate for known temperature variations in key laser characteristics such as slope efficiency; and (v) monitoring functions that report various parameter values related to the transceiver operating characteristics and environment such as laser bias current, laser output power, received power level, supply voltage and temperature. As such, controller functions and the data contained therein are integral to network performance and, consequently, would be useful to end users such as network administrators if only the data was easily accessible.
Unfortunately, conventional host equipment often lack the ability to access the data. Other host equipment, which may be capable of accessing diagnostic data, typically lacks the means to convey the diagnostic data to an end user in an easy manner. The information can only be obtained through effort that includes additional equipment. It is therefore difficult for network administrators to determine the status of an individual link and to troubleshoot complex systems.